Cumulative radiation in critically ill patients: a retrospective audit of ionising radiation exposure in an intensive care unit

Objective: Ionising radiation is a valuable tool in modern medicine including for patients in an intensive care unit (ICU). However, clinicians are faced with a trade-off between benefit of information received from procedure versus risks associated with radiation. As a first step to understanding the risk and benefits of radiation exposure to ICU patients, we aimed to assess the cumulative levels of ionising radiation patients receive during their ICU stay. Design: Retrospective audit. Setting: A single tertiary care ICU in South Australia. Participants: This audit included 526 patients admitted to the ICU at Flinders Medical Centre, Adelaide, SA, for longer than 120 hours (long stay) over a 12-month period from April 2015 to April 2016. Main outcome measures: Cumulative radiation exposure to ICU patients. Results: The 526 patients audited underwent 4331 procedures totalling 5688.45 mSv of ionising radiation. The most frequent procedure was chest x-ray (82%), which contributed 1.2% to cumulative effective dose (CED). Although only 3.6% of the total procedures, abdominal and pelvic computed tomography (CT) contributed the most to CED (68%). Over 50% of patients received less than 1 mSv CED during their stay in the ICU. However, 6% received > 50 mSv and 1.3% received > 100 mSv CED. Trauma patients received significantly higher CED compared with other admission diagnoses, and CED increased with length of stay. Conclusion: Most ICU patients received low CED during their stay, with the majority receiving less than the recommended limit for members of the public (1 mSv). These results may educate clinicians regarding radiation exposures in ICU settings, highlighting the relatively low exposures and thus low risk to the patients.